DOT O706 means tires manufactured 7th week of 2006. Tires are recommended to be changed from 5 to 7 years and the tires are 8 years old.

My tires DOT are 3809 - 38th week of 2009.  The tires will be 5 years old somewhere around OCT.

After researching for a year on this and other forums (RV plus Truck related) I found the Michelin XPS RIBS seemed to have the most positive comments. Many of the folks reported getting more miles than expected out of these tires with little or no problems other than road hazard related. These are LT tires.

I bought a set 3 years ago for the 5th wheel and have been pleased with the performance.

As a side note, yesterday I took a look at the rear tires on my old truck that I used to tow the 5th wheel with discovered I had XPS RIBS... I knew they were Michelins but didn't realize they were RIBS. I had bought them used at a swap meet so I don't know how many miles they had but the tread was 80%. I put another 25,000 miles before I bought the new truck and these tires still have good tread but are beginning to crack due to age. The old truck is rarely driven (only a few miles round trip) so no need to replace the tires.

My vote is for Michelin XPS RIBS.... about $230 per tire mounted.

For the 17.5" tire and wheel combo, with Goodyear G-114's (load range H), I was quoted $615 each which included shipping, at Trailer Tire and Wheel.

Our '06 TT had Marathons and they worked well on it - although it's max gross was only 10.5k lbs. Our new/old Montana had them, with date stamps of '09. Since it grosses at 15.6k, I changed them right away last year to Firestone LTs with not older than 3 months date stamps. These will be replaced by '18 at the latest, to either G614s or RIBS (G117s & new wheels if I hit a lottery!). Couldn't quite afford them right after buying the Montana and a new/old truck!

Stay with the Goodyears.....................Do not put any Chinesium crap on for tires.

Time for my periodic basic tire review for those viewing this topic that are scratching their heads. 

Tire "size" includes all of the numbers.  You can't leave any of them out when talking tire sizes.  Using the following example:  235/85R16

• The 235 is the width of the tire in millimeters when it is properly inflated for the load it is carrying.
• The 85 is the aspect ratio or sidewall height - the distance from the tread to the rim (the hole in the tire) is 85% of the width (235mm X 85%)
• "R" stands for radial
• The 16 is the diameter of the hole in the tire which matches up with the size rim (wheel)

There may be letters in front of the tire size:

• P = Passenger Tire (Used on most passenger vehicles and pick-ups that are half-ton or less)
• LT = Light Truck Tire (Used on three quarter ton and larger pick-ups, cargo vans, lighter motorhomes, and heavy trailers)
• ST = Special Trailer Tire (Used on boat trailers, utility trailers, and lighter RV trailers)
• NO Letter = Commercial Bus or Truck Tire (Used on heavy duty trucks, Class A motorhomes, Bus Conversions, Buses, etc.)

The sidewall will also include a maximum load capacity and inflation pressure when used in a single and dual application.  ST tires usually don't include a "dual" rating because they are not designed to be used as duals.

The sidewall will also include a load range.  It's spelled out Load Range "_" with a letter in the blank.  Except Michelin just uses the abbreviation LR_ and it can be hard to see.  Load Ranges are an indicator of "ply ratings" - not actual plies, but ply rating for comparing strength and load capacities.

• Load Range C = 6-ply rated
• Load Range D = 8-ply rated
• Load Range E = 10-ply rated
• Load Range F = 12-ply rated
• Load Range G = 14-ply rated
• Load Range H = 16-ply rated

Tires of the same size come in different load ranges.  It is IMPERATIVE that you match load ranges when replacing tires.  We've seen numerous instances where inadequate load range tires (same size, but wrong load range) have been put on by tire shops.  This results in two major problems: 1) Your tire doesn't have the carrying capacity it should and will likely be overloaded, and 2) You will probably inflate it the same as the other tires, so it may be dangerously over-inflated.  An E range tire has a max inflation pressure of 80 psi, and we've seen those put on where all the other tires are G range which has a max inflation of 110 psi and the owner was inflating an 80 psi tire to 110 psi -very dangerous.

Now, the original poster had ST 235/85R16 tires.  Those are a Special Trailer tire designed to roll along behind.  There isn't much tread which helps with the scuffing when the trailer is making tight turns in forward or reverse.  The Goodyear Marathons that folks mention are ST tires which are put on many RV trailers - they come in many different sizes and load ranges, but the most common is the ST 235/80R16, Load Range E with a max carrying capacity of 3420 lbs at a max air pressure of 80psi.

The suggested Goodyear G614s are LT tires, not ST.  They are LT 235/85R16, Load Range G with a max carrying capacity of 3750 (single) at a max air pressure of 110 psi.  So, they will fit on the original poster's wheels and provide more carrying capacity.  However, whenever we change to higher capacity tires, we need to make sure the wheels (rims) are capable of handling the higher load capacity and the higher inflation pressures.  If the rims are only rated at 3500 lbs and 80 psi, we can't inflate the new tires past 80 psi and their carrying capacity at that inflation is only 3042 lbs, so we haven't gained a thing, but rather have lost carrying capacity.

That's why changing tires becomes complicated.  Often it is necessary to change the tires AND the wheels to get the proper benefit.  And then, we might still be limited by the capacity of the axles.  So, a simple change in tires can result in also upgrading wheels and axles to get the full benefit of the change.

Now, in our experience with weighing RVs and hearing lots of stories (nothing scientific), we've found that both the ST tires and the Goodyear G614 LT tires perform admirably as long as the loads on the tires don't approach the maximum load capacities of the tires.  However, we have noted several failures when the loads on the tires get close to their max capacities (not just over their limits, but close to).  Remember, loads shift as you are going down the road, so if you have your RV weighed and you are under all of your load capacities on your tires, but just barely, chances are the tires become overloaded as you travel when weight shifts back and forth, thus damaging the tires and ultimately resulting in failures.  This load shifting is also why both Goodyear and Michelin recommend inflating tires 5 - 10 psi higher than their inflation charts indicate for the loads so there is extra cushion.

This is why we are proponents of having more tire capacity than your weights would indicate you need, especially if you are full-timing, part-time full-timing, or taking long extended trips.  It's certainly different when almost everything you own is in your RV and you are loaded to capacity rather than taking an occasional short trip where you are lightly loaded.

Okay, personal opinion for full-timers or those that will load their trailers to full capacity.  I prefer the Goodyear G614s LT tires for two-axle trailers with a GVWR of 14,000 lbs up to 16,000 lbs.  The math says they should be good up to about 18,000 lbs GVWR, but I prefer a larger safety margin (as a full-timer loading to max).  The tires are the foundation of our traveling homes, and I want my best equipment to be the tires, wheels, brakes, and suspension.  As we approached 18,000 lbs total weight, we noticed issues with our G614s, so we switched in 2008 to the Goodyear G114 275/15R17.5, Load Range H commercial tires with a max capacity of 4805 lbs at 125 psi.  That required new rims, but the actual overall dimension of the tires is just a fraction off of the G614, so we didn't have any clearance issues.  One of the best decisions we've ever made, and I just put on a new set of G114s - it's just an excellent tire (and the price reflects it at over $400 per tire).

Now, with all of that said, there are other really good tires out there.  Michelins are great tires, but their trailer tires tend to only be speed rated for 65 mph.  That's about a maximum speed for us, but again I like the safety margin of the G114s which are rated to 75 mph.  There are certainly other options at lower prices, but we simply know the Goodyears from personal experience and we'll stick to what we know - G614s if not loading them too close to max, and G114s for heavier two-axle trailers.

Just my opinion. 

Something to keep in mind is the fact you can sell the old rims and tires and recoup part of the cost of new ones.

Our 2010 Mobile Suites came with load range G Vanguards (Chinese) with good tread.  I plan to sell these through Craigslist or wherever else I can.  Hopefully for around $600.

el Rojo wrote:

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Thanks Howard and Bill. I just got off the phone with Trailer Tire and Wheel. I'm going with the 215/75R/17.5 Goodyear G114 with new wheels. I got a delivered price of $3305 for 5 mounted and balanced. These tires should have plenty of safety margin.

Once again, thanks!

Red

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 We bought these same tires through Trailer Tire and Wheel and could not be happier. It is nice to have the peace of mind when going down the road. I listed my old set on Craigslist and ended up getting 700 for them. 

Jim